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Articles 31 - 60 of 132
Full-Text Articles in Chemical Engineering
Materiały Odstresowujące, Wojciech M. Budzianowski
Materiały Odstresowujące, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Determination Of Airborne Nanoparticles From Welding Operations, João F. Gomes
Determination Of Airborne Nanoparticles From Welding Operations, João F. Gomes
João F Gomes
The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas (TIG), metal active gas (MAG) of carbon steel and friction stir welding (FSW) of aluminium) in terms of deposited area in pulmonary alveolar tract using a Nanoparticle Surface Area Monitor (NSAM) analyzer. The obtained results showed the dependence from process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and …
Exposure To Airborne Ultrafine Particles From Cooking In Portuguese Homes, João F. Gomes
Exposure To Airborne Ultrafine Particles From Cooking In Portuguese Homes, João F. Gomes
João F Gomes
No abstract provided.
Hydrogen Production From Biogas By Oxy-Reforming: Reaction System Analysis, Aleksandra Terlecka, Wojciech M. Budzianowski
Hydrogen Production From Biogas By Oxy-Reforming: Reaction System Analysis, Aleksandra Terlecka, Wojciech M. Budzianowski
Wojciech Budzianowski
Oxy-reforming is emerging as an interesting alternative to conventional methods of hydrogen generation. The current article characterises this process through analysis of individual reactions: SMR (steam methane reforming), WGS (water gas shift) and CPO (catalytic partial oxidation). Analyses relate to optimisation of thermal conditions thus enabling cost-effectivenes of the process.
Assessment Of Exposure To Airborne Ultrafine Particles In The Urban Environment Of Lisbon, Portugal, João F. Gomes
Assessment Of Exposure To Airborne Ultrafine Particles In The Urban Environment Of Lisbon, Portugal, João F. Gomes
João F Gomes
The aim of this study was the assessment of exposure to ultrafine in the urban environment of Lisbon, Portugal, due to automobile traffic, and consisted of the determination of deposited alveolar surface area in an avenue leading to the town center during late spring. This study revealed differentiated patterns for weekdays and weekends, which could be related with the fluxes of automobile traffic. During a typical week, ultrafine particles alveolar deposited surface area varied between 35.0 and 89.2 mm2/cm3, which is comparable with levels reported for other towns such in Germany and the United States. These measurements were also complemented …
Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes
Study On The Use Of Mgal Hydrotalcites As Solid Heterogeneous Catalysts For Biodiesel Production, João F. Gomes
João F Gomes
This paper, reports experimental work on the use of new heterogeneous solid basic catalysts for biodiesel production: double oxides of Mg and Al, produced by calcination, at high temperature, of MgAl lamellar structures, the hydrotalcites (HT). The most suitable catalyst system studied are hydrotalcite Mg:Al 2:1 calcinated at 507 ºC and 700 ºC, leading to higher values of FAME also in the second reaction stage. One of the prepared catalysts resulted in 97.1 % Fatty acids methyl esters (FAME) in the 1st reaction step, 92.2 % FAME in the 2nd reaction step and 34 % FAME in the 3rd reaction …
The Impact Of Driving Conditions On Phev Battery Performance, Nathan Christensen, John Patten, Steven Srivastava, Gary P. Nola
The Impact Of Driving Conditions On Phev Battery Performance, Nathan Christensen, John Patten, Steven Srivastava, Gary P. Nola
john a patten
The battery performance of a modified Prius with a 5 kWh plug-in battery was documented for a year to determine the impact of environmental conditions and user attributes on vehicle performance. Both fuel economy and pure electrical efficiency were compared to ambient temperature. The fuel economy has a positive relationship with ambient temperature until approximately 70˚F where the efficiency begins to drop. Electrical performance has a positive linear relationship with ambient temperature. With the emergence of electric vehicles (EVs) and PHEVs from a variety of automotive manufacturers, information on EV and PHEV performance for consumers will become more important.
Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes
Notice On A Case Study On The Utilization Of Wind Energy Potential On A Remote And Isolated Small Wastewater Treatment Plant, João F. Gomes
João F Gomes
Small wastewater treatment plants (WWTP) are frequently located, by necessity, in remote and isolated sites, which increases the difficulty of its energy supply. Some of them are located near the seaside, in environmental sensible zones, and due to tourism activity of these sites, seasonal effects related with population size fluctuation can occur, which can originate certain inefficiencies concerning WWTP design and energy supply. The objective of this paper is to describe a step by step procedure for evaluation of the wind potential of sites that are dependent of in-situ energy generation, as well as, a case study on the utilization …
New Nanosystem Mixed Reactor For Urban Wastewater Treatment, Masoud Rastegar, Kamran Rahmati Shadbad
New Nanosystem Mixed Reactor For Urban Wastewater Treatment, Masoud Rastegar, Kamran Rahmati Shadbad
Masoud Rastegar
No abstract provided.
New Nanosystem Mixed Reactor For Urban Wastewater Treatment, Masoud Rastegar
New Nanosystem Mixed Reactor For Urban Wastewater Treatment, Masoud Rastegar
Masoud Rastegar
No abstract provided.
Behavior Of Hydrophobic Ionic Liquids As Liquid Membranes On Phenol Removal: Experimental Study And Optimization, Yee Sern Ng, Jayakumar Natesan Subramaniam, Mohd Ali Hashim
Behavior Of Hydrophobic Ionic Liquids As Liquid Membranes On Phenol Removal: Experimental Study And Optimization, Yee Sern Ng, Jayakumar Natesan Subramaniam, Mohd Ali Hashim
Ng Yee-Sern
Room temperature ionic liquids show potential as an alternative to conventional organic membrane solvents mainly due to their properties of low vapor pressure, low volatility and they are often stable. In the present work, the technical feasibilities of room temperature ionic liquids as bulk liquid membranes for phenol removal were investigated experimentally. Three ionic liquids with high hydrophobicity were used and their phenol removal efficiency, membrane stability and membrane loss were studied. Besides that, the effects of several parameters, namely feed phase pH, feed concentration, NaOH concentration and stirring speeds on the performance of best ionic liquid membrane were also …
Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes
Study On The Glycerolysis Reaction Of High Free Fatty Acid Oils For Use As Biodiesel Feedstock, João F. Gomes
João F Gomes
Biodiesel is the main alternative to fossil diesel and it may be produced from different feedstocks such as semi-refined vegetable oils, waste frying oils or animal fats. However, these feedstocks usually contain significant amounts of free fatty acids (FFA) that make them inadequate for the direct base catalyzed transesterification reaction (where the FFA content should be lower than 4%). The present work describes a possible method for the pre-treatment of oils with high content of FFA (20 to 50%) by esterification with glycerol. In order to reduce the FFA content, the reaction between these FFA and an esterification agent is …
Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes
Design Of A New Test Chamber For Evaluation Of The Toxicity Of Rubber Infill, João F. Gomes
João F Gomes
A test chamber was projected and built (according to ISO 16000-9 Standard) to simulate atmospheric conditions experienced by rubber infill (when applied in synthetic turf pitches) and measure accurately the airborne emissions of pollutants such as dusts and volatile organic compounds (VOC), as well as pollutants present in leacheates. It should be pointed out that standard ISO 16000-9 is only concerned with the determination of the emission of VOC from building products and furnishing (not specific of synthetic turf materials), while other standards are concerned with the emission of leacheates only. This procedure is to be considered as a technical …
What Is A Chemical Engineer ?, João F. Gomes
On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes
On The Toxicological Effects Of Airborne Nanoparticles From Welding Processes, João F. Gomes
João F Gomes
No abstract provided.
Termodynamika Procesowa (Dla Me Aparatura Procesowa) Ćw., Wojciech M. Budzianowski
Termodynamika Procesowa (Dla Me Aparatura Procesowa) Ćw., Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
The Analysis Of Heat Transfer In A Gas-Gas Heat Exchanger Operated Under A Heat-Recirculating Mode, Mariusz Salaniec, Wojciech M. Budzianowski
The Analysis Of Heat Transfer In A Gas-Gas Heat Exchanger Operated Under A Heat-Recirculating Mode, Mariusz Salaniec, Wojciech M. Budzianowski
Wojciech Budzianowski
The present paper presents the analysis of heat transfer in a gas-gas heat exchanger operated in a heat-recirculating mode.
An Overview Of Technologies For Upgrading Of Biogas To Biomethane, Wojciech M. Budzianowski
An Overview Of Technologies For Upgrading Of Biogas To Biomethane, Wojciech M. Budzianowski
Wojciech Budzianowski
The present contribution presents an overview of technologies available for upgrading of biogas to biomethane. Technologies under study include pressure swing adsorption (PSA), high-pressure water wash (HPWW), reactive absorption (RA), physical absorption (PA), membrane separation (MS) and cryogenic separation (CS).
Influence Of Energy Policy On The Rate Of Implementation Of Biogas Power Plants In Germany During The 2001-2010 Decade, Izabela Chasiak, Wojciech M. Budzianowski
Influence Of Energy Policy On The Rate Of Implementation Of Biogas Power Plants In Germany During The 2001-2010 Decade, Izabela Chasiak, Wojciech M. Budzianowski
Wojciech Budzianowski
The current article describes energy policy tools, which caused intensive development of biogas-based power generation in Germany during the 2001-2010 decade. The German system of financial support to biogas power plants is presented in details. It is shown that in Germany, i.e. in a country characterised by similar climate and potentials to renewable energy to Poland, biogas power plants cover 10,7% of electricity demands in 2010, while all renewable energy sources cover only 5,4% of electricity demands. It is emphasised that under favourable Polish energy policy, the development of biogas energy can be very rapid.
Mechanical Properties Of High Blaine Portland Cement, Masoud Rastegar, Kamran Rahmati Shadbad, Ali Hadidi
Mechanical Properties Of High Blaine Portland Cement, Masoud Rastegar, Kamran Rahmati Shadbad, Ali Hadidi
Masoud Rastegar
No abstract provided.
Energetyka Niskoemisyjna, Wojciech M. Budzianowski
Energetyka Niskoemisyjna, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Comparison Of Theory And Experiments For Dispersion In Homogeneous Porous Media, Mark Porter, Francisco Valdes-Parada, Brian Wood
Comparison Of Theory And Experiments For Dispersion In Homogeneous Porous Media, Mark Porter, Francisco Valdes-Parada, Brian Wood
Francisco J. Valdes-Parada
Modeling dispersion in homogeneous porous media with the convection–dispersion equation commonly requires computing effective transport coefficients. In this work, we investigate longitudinal and transverse dispersion coefficients arising from the method of volume averaging, for a variety of periodic, homogeneous porous media over a range of particle Péclet (Pep) numbers. Our objective is to validate the upscaled transverse dispersion coefficients and concentration profiles by comparison to experimental data reported in the literature, and to compare the upscaling approach to the more common approach of inverse modeling, which relies on fitting the dispersion coefficients to measured data. This work is unique in …
Bacterial Chemotaxis In Porous Media: Theory Derivation And Comparison With Experiments, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood
Bacterial Chemotaxis In Porous Media: Theory Derivation And Comparison With Experiments, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood
Francisco J. Valdes-Parada
Chemotaxis is the movement of organisms toward or away from the concentration gradient of a chemical species. Microbial chemotaxis has been shown to significantly increase contaminant degradation in subsurface environments with respect to traditional methods such as pump-and-treat. This type of transport phenomena often involves diffusion and convection along several scales. In this work we use the method of volume averaging to upscale the governing equations for in situ bioremediation by bacterial chemotaxis. The results are effective medium mass balance equations for both the bacteria and the chemical attractant. These equations are expressed in terms of average transport coefficients, which …
Interpretation Of Closure Variables In Upscaling, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood
Interpretation Of Closure Variables In Upscaling, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood
Francisco J. Valdes-Parada
In many engineering applications, it is common to nd systems that involve transport at several scales. Despite the increasing computational capabilities, it is still not feasible to model a complete macroscopic system by direct numerical simulations at the microscale. Actually, it is more convenient to derive models at an intermediate level of scale between the microscale and the macroscale; this is the average scale. The derivation of models at this scale can be carried out by means of the method of volume averaging. The results from this method are averaged transport equations expressed in terms of eective medium coecients that …
One-Domain Approach For Heat Transfer At The Fluid-Porous Medium Inter-Region, Francisco J. Valdes-Parada, Carlos G. Aguilar-Madera, Benoît Goyeau, J. Alberto Ochoa-Tapia
One-Domain Approach For Heat Transfer At The Fluid-Porous Medium Inter-Region, Francisco J. Valdes-Parada, Carlos G. Aguilar-Madera, Benoît Goyeau, J. Alberto Ochoa-Tapia
Francisco J. Valdes-Parada
The modeling of transport phenomena in the zone of rapid changes between a fluid and a porous medium (i.e., the interregion) can be carried out using two distinctive approaches. The first one, generally called the one-domain approach, describes transport phenomena in the whole fluid-porous system using averaged macroscopic conservation equations including spatially dependent effective properties. These coefficients reduce to their respective constant values in the homogeneous fluid and porous regions of the system. As an alternative, the two-domain approach uses the transport equations with constant coefficients in the entire domain of each region, including the zone of drastic changes. To …
Derivation Of Complete Jump Boundary Conditions Between Homogeneous Media, Francisco J. Valdes-Parada, Benoît Goyeau, J. Alberto Ochoa-Tapia
Derivation Of Complete Jump Boundary Conditions Between Homogeneous Media, Francisco J. Valdes-Parada, Benoît Goyeau, J. Alberto Ochoa-Tapia
Francisco J. Valdes-Parada
The modeling of transport phenomena between homogeneous regions requires the derivation of jump boundary conditions. These conditions account for the rapid spatial variations of the transport properties taking place near the dividing surface of the media. There has been a long debate in the literature about whether the discontinuity should apply to the fields (e.g., velocity, temperature, concentration) or to their fluxes. In this work, a general methodology giving rise to jump conditions for both the fields and the fluxes is proposed. This method, besides using a microscopic closure, introduces macroscopic deviation fields that lead to closure schemes for both …
Modelo Aproximado Del Coeficiente De Dispersión En Medios Porosos, Francisco J. Valdes-Parada, Helen D, Lugo-Méndez, J. Alberto Ochoa-Tapia
Modelo Aproximado Del Coeficiente De Dispersión En Medios Porosos, Francisco J. Valdes-Parada, Helen D, Lugo-Méndez, J. Alberto Ochoa-Tapia
Francisco J. Valdes-Parada
En este trabajo, se utiliza el método del promedio volumétrico para la predicción del coeficiente efectivo de dispersión y la teoría de las funciones de Green para encontrar una solución analítica aproximada. Como simplificación de la celda representativa del medio poroso homogéneo, se usó la celda de Chang, imponiendo la condición de flujo reptante. Para corroborar los resultados se determinó numéricamente el coeficiente efectivo, en celdas unitarias periódicas usando el programa comercial basado en el método de de elemento finito COMSOL Multiphysics. El coeficiente efectivo de dispersión analítico obtenido en este trabajo presenta una tendencia análoga al numérico, además de …
Diseño De Una Parrilla Para La Reducción De Pérdidas De Energía En Estufas Convencionales, Francisco J. Valdes-Parada, Victor Castillo-Jimenez, Alberto Gabino-Zamora, Armando Astudillo-Velázquez
Diseño De Una Parrilla Para La Reducción De Pérdidas De Energía En Estufas Convencionales, Francisco J. Valdes-Parada, Victor Castillo-Jimenez, Alberto Gabino-Zamora, Armando Astudillo-Velázquez
Francisco J. Valdes-Parada
Las estufas de gas convencionales tienen, por lo general, pérdidas considerables de energía alrededor del quemador, lo que disminuye su eficiencia e incrementa el consumo de recursos. Para atender este problema, en este trabajo se propone concentrar la mayor parte del calor hacia una sola región, para poder obtener la mayor cantidad de energía sin tener que suministrar más combustible y de esta manera aumentar la eficiencia de estufas convencionales. Para ello, se construyó un prototipo experimental a partir de cálculos de diseño teóricos. Con el prototipo ahorrador de energía se consiguió un ahorro hasta del 40% del consumo de …
Análisis De La Transferencia De Calor En Azoteas Verdes, Francisco J. Valdes-Parada, Verónica Freyre-Fonseca
Análisis De La Transferencia De Calor En Azoteas Verdes, Francisco J. Valdes-Parada, Verónica Freyre-Fonseca
Francisco J. Valdes-Parada
El problema de las islas urbanas de calor contribuye a los drásticos cambios climáticos que se sufren en ciudades densamente pobladas. Para atender este problema se tienen diversas alternativas, entre las cuales se contempla incorporar zonas verdes (e.g., paredes y azoteas verdes) en edificaciones que contrarresten los efectos de calentamiento excesivo. En este trabajo se estudia la transferencia de calor en edificaciones típicas de la ciudad de México utilizando diferentes configuraciones de zonas verdes. Los resultados muestran que el utilizar azoteas verdes tiene un efecto estabilizador en los perfiles locales de temperatura; sin embargo a nivel de toda una edificación, …
Escalamiento De Ecuaciones De Transporte De Energía En Un Tanque Agitado, Francisco J. Valdes-Parada, J. Alberto Ochoa-Tapia
Escalamiento De Ecuaciones De Transporte De Energía En Un Tanque Agitado, Francisco J. Valdes-Parada, J. Alberto Ochoa-Tapia
Francisco J. Valdes-Parada
El planteamiento de balances para el diseño de equipos de transporte y reacción en Ingeniería Química suele llevarse a cabo mediante la aplicación de balances de coraza macroscópicos. Esta forma de proceder tiene la desventaja que no proporciona las restricciones y suposiciones que sustentan al modelo resultante, lo cual puede tener consecuencias graves en actividades de diseño y control de procesos. Una alternativa a esta metodología consiste en llevar a cabo un proceso de escalamiento de las ecuaciones de transporte válidas en la microescala, identificando sistemáticamente las suposiciones necesarias para la deducción del modelo macroscópico. En este trabajo se analiza …